NEW YORK — Sales of personal computers in the U.S. didn’t get any boost from the launch of Windows 8, confounding the hopes of Microsoft and PC makers, research firm NPD Group said Thursday.

In the three weeks after Windows 8 launched Oct. 26, sales of Windows PCs and tablet computers fell 21 percent compared with a year earlier, according to NPD, which tracks U.S. retail sales.

There’s no sign that Windows 8 made things worse for PC makers. Rather, NPD said the weak sales are a continuation of a year-long trend.

U.S. consumers appear more interested in spending electronics dollars on smartphones and tablets than on upgrading their computers.

Microsoft Corp. developed Windows 8 with tablets and touch screens in mind. The new operating system features a new look and is designed to make desktops and laptops work more like tablets.

The Redmond, Wash., company is supporting the launch with its largest ad campaign.

PC makers were officially optimistic and have largely switched their consumer-focused product lines over to Windows 8, but they were cautious about stocking large numbers of PCs ahead of the launch. Reviews of the new operating system were mixed.

More in Business

Fast forward to today, and Larkburger is celebrating its 10th anniversary, having grown from one restaurant in Edwards to 12 locations in the state amid increasingly fierce competition in the “better burger” world.

On the day President-elect Donald Trump lashed out at Boeing for the cost of replacing Air Force One, mechanics and engineers at the planemaker’s South Carolina factory were focused on another challenge: making the first 787-10 Dreamliner.

The trucking industry scored a victory this week when Republican lawmakers effectively blocked Obama administration safety rules aimed at keeping tired truckers off the highway. But there’s more coming down the road.